This video, via John L Rice, is an informal comparison of the sound of six different large-format (5U) modular synthesizer filters:

• 00:23 MOTM-440
• 06:05 MOTM-490 
• 11:59 Croglin
• 16:07 Sea Devils
• 21:44 9504A
• 28:18 M506

Rice explains the basic patch:

3 x MOTM-300 VCOs, PWM’d by a MOTM-380 LFO and pulse outputs into a STG Mixer, then to one of the VCF’s and then to a MOTM-190 VCA. Two different MOTM-800’s were used, one for the VCA and one for the VCF. Sequencer was a Moon Modular 569.

On the first couple VCF’s I also used a COTK C964 Ratchet Sequencer module and a third MOTM-800 into the VCF but, I forgot to use it on the last 3 or 4 VCF’s! :-/